Drew Peterson, a former Chicago-area police officer imprisoned for murdering his wife, was found guilty on Tuesday of trying to hire someone in 2014 to kill the prosecutor who convicted him, prosecutors said.

Peterson, 62, was found guilty of solicitation of murder and solicitation of murder for hire. He faces mandatory sentences of 20 to 40 years for the first charge and 15 to 30 years for the second charge, according to a statement by the Illinois Attorney General’s office, which helped prosecute the case.